Field of the Invention
The present invention relates generally to electrically operated door access systems in which the door is either unlocked or opened, or both unlocked and opened, by accessing an electronic control system, and more particularly to an improved pressure-actuated control bar or handle which may be located on a door through which access is controlled by the electrically operated door access system, whereby the pressure-actuated control bar is used to trigger unlocking or opening, or both unlocking and opening, of the door following pressure being exerted on the pressure-actuated control bar by an individual desiring access or egress through the door.
Hardware and systems for controlling egress and access through doors may predominantly be classified into one of two categories. The first category is that of hardware and systems which are designed to limit and control access and egress through doors. Devices falling into this classification are generally utilized for theft-prevention or to establish a secured area into which (or from which) entry is limited. The second category is that of hardware and systems which are designed to facilitate access through doors by opening the doors in a manner not requiring great strength or facility by the person desiring access. Devices falling into this second classification are used to automate the opening of a door in an easy, yet controlled, manner suitable for use by handicapped individuals, for example.
The first of these two categories includes controlled access security doors and operating systems for such doors. Such doors and systems have evolved over the years from simple doors having heavy duty mechanical locks thereon to sophisticated egress and access control devices. In bygone times, heavy duty chains and locks were the norm on security doors which were not generally used, or which were used to prevent theft or vandalism. However, fire codes have made such relatively simple door locking systems obsolete, at least in most developed countries. Emergency exit doors are required by law to be provided in all commercial buildings, and such doors must be operative in the event of a fire, earthquake, or other emergency.
These exit doors are typically provided with heavy horizontal push bars, which unlock the door upon actuation and which may provide an alarm of some sort. The early alarms on such doors were either mechanical in nature, such as wind-up alarms contained on the push bar mechanism, or completely separate electrical circuits actuated by a switch opened as the door was opened. Accordingly, egress from such doors was immediate, and, although egress was accompanied by an alarm, typically the person leaving through the door was long gone by the time security personnel arrived.
Many stores suffer great losses through emergency doors, with thieves escaping cleanly through the emergency doors with valuable merchandise. In addition, industrial companies also suffer pilferage of valuable equipment and merchandise through such emergency exit doors. While one solution is to have a greater number of security personnel patrolling the emergency exit doors, to do so is also an expensive solution.
As might be expected, the art reflects a number of emergency exit access activation devices which attempt to solve this problem. A first type of device is found in U.S. Pat. No. 4,257,631, to Logan, Jr., which describes a system activated by a push bar which, upon depression, moves a switch carried by the door to sound an alarm and start a timer delay. After the delay, the door is unlocked.
This type of device in which a push bar containing an electrical switch therein is used to initiate a request for access or egress is by far the most common. It has not always been viewed as the optimum solution, however, due to the difficulty in making it durable and long lasting in addition to being relatively simple and inexpensive. Several other types of systems have been proposed, and, although none of these systems has found great acceptance, a brief discussion of them is in order.
U.S. Pat. No. 4,328,985 and U.S. Pat. No. 4,354,699, both also to Logan, teach a hydraulic system for accomplishing the delay prior to unlocking the door, and a retrofit locking device of the same type which is usable with any door latching system, respectively. These two systems are thus mechanical rather than electrical in nature.
U.S. Pat. No. 4,652,028 and U.S. Pat. No. 4,720,128, to Logan et al. and to Logan, Jr., et al., respectively, teach an electromagnet mounted on a door jamb, an armature on the door held by the electromagnet to retain the door in the closed position, and a switch mounted near the electromagnet which is used to indicate when the door is being opened or tampered with. The Logan, Jr. et al. '128 patent also adds a set of contacts to confirm that the armature properly contacts the electromagnet. These systems have no switch located in a door access bar.
As mentioned above, the second category of hardware and systems includes devices and systems which are designed to facilitate access through doors by opening the doors in a manner not requiring great strength or facility by the person desiring access. One example of such a device is the type of door commonly found in supermarkets, which is typically radar controlled. Another example is a power actuated door in a hospital corridor, wherein when a wall switch is depressed the door automatically opens.
Both of the two categories of devices discussed above are beneficial, yet both categories of devices still possess several disadvantages and are illustrative of problems inherent in the art. For example, the preferred type of door access bar, the type containing an electrical switch therein, has several disadvantages. First, in order for the switching mechanism to operate, there must be a minimal amount of free movement in the bar. The use of a limit switch in the bar requires the switch to be precisely adjusted to operate properly. In addition, one or more springs must be utilized in order to keep the switches in the open position when the door access bar is not being depressed. In addition, the presently known electrical switch type door access bar is mechanically fairly complex, and not inexpensive to manufacture.
Referring now to the automatic door opening mechanisms discussed above, there are also problems in the implementation insofar as these devices may be used by handicapped persons. This is because the types of automatic doors discussed above do not automatically stop once they begin to open. In addition, such devices do not comply with safety regulations such as those found in The Americans With Disabilities Act, and thus are no longer be commercially competitive. This Act and related requirements direct that the doors must be stoppable in an intermediate position upon the exertion of a minimal force.
It is accordingly the primary objective of the present invention that it present a door access bar which has a greatly improved electromechanical mechanism through which mechanical contact by a user with the door access bar is translated into an electrical output which may be utilized to initiate the process of unlocking the door on which the door access bar is located. In this regard, it is a closely related objective of the present invention that the conventional limit switch mechanism be entirely replaced with a different type of switch mechanism which is more dependable and long lasting than conventional limit switches, and which also requires no adjustment throughout its lifetime.
It is a further objective of the door access bar of the present invention that it require only minimal movement of the door access bar to initiate the electrical output indicating a desire for access or egress. In addition, it is desired that the conventional coiled springs used in door access bars be eliminated in favor of an improved mechanical design. It is a related objective that only a slight degree of force need be applied to the door access bar in order to obtain its electrical output. It is a further objective of the present invention that the minimum amount of force required to initiate the electrical output required to indicate a desire for access or egress be fully adjustable over an appreciable range of force.
It is another principal objective of the improved door access bar mechanism of the present invention that it be adaptable for use as a control mechanism for operating an automatically opening door of the type used by handicapped individuals. It is a closely related objective that the switch mechanism contained in the door access bar of the present invention be adaptable as a push/pull door access handle to control both the opening of a door when the door access handle is pulled, as well as the stopping, in an intermediate position, of the door when the door access handle is pushed. The adapted door access handle must require only a minimal force to actuate it in either the pushing movement or the pulling movement thereof in order to safely meet the needs of the handicapped, as well as to meet the requirements of The Americans With Disabilities Act.
The door access bar or handle of the present invention must also be of a construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user. In order to enhance the market appeal of the door access bar or handle of the present invention, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages and objectives of the present invention be achieved without incurring any substantial relative disadvantage.